Demonstration of the nanosize effect of carbon nanomaterials on the dehydrogenation temperature of ammonia borane.

Ammonia borane (AB, NHBH) is a highly promising hydrogen storage material, but its high dehydrogenation temperature hinders its wide use in practice. The infiltration of AB into the pores of porous materials can lower the dehydrogenation temperature by what is known as the nanoconfinement effect. Nonetheless, it is unclear as to whether this phenomenon stems from a catalytic effect or the nanosize effect. In this work, carbon nanomaterials with a uniform pore size and with inertness to AB were chosen as nanoscaffolds without catalytic sites to control the particle size of AB. It is proved experimentally that the dehydrogenation temperature of AB is inversely proportional to the reciprocal of the particle size, which means that the nanoconfinement effect can be caused solely by the nanosize effect without a catalytic effect.